The larger Coco Solo Hospital was constructed in the summer of 1941.[3] The area containing it was transferred from the civil part of the Panama Canal Zone to the naval part when Franklin Roosevelt signed Executive Order 8981 on December 17, 1941.[6] During World War II, Coco Solo also served as a Naval Aviation Facility, housing a squadron of P-38 Lightning aircraft.

By the 1960s, no US Navy vessels remained, only some support staff and housing. Coco Solo was also home to the Atlantic Side High School and Cristobal Junior and Senior High, which in the late 1970s was also the high school for Panamanians from Rainbow City. Also located in Coco Solo was the local commissary where Zonians would purchase food and clothing. At the far end of Randolph Road was Fort Randolph, unused except for military training exercises, and where the Fort Randolph Riding Club was located as used by the Canal Zone Horsemen's Association.

Until the mid-1990s, the town site of Coco Solo was used by the civilian employees of the Panama Canal as a residential area. Navy communications operations at the nearby Galeta Island facility were conducted as well.

After the return of the Panama Canal to Panamanians in 1999, US military activity ceased at both Coco Solo and Galeta Island.